This disclosure relates in general to copier/printers, and more particularly, to an automatic print media size detector.
Printing systems commonly use a plurality of paper trays to enable printing on different sizes of paper. In order to enhance productivity of the apparatus, it is desired to know exactly the size paper present in the paper tray to enhance the printing operation on the paper. By knowing what size paper is present in the paper tray, throughput of the printing apparatus can be maximized to reduce the time required for a printing operation.
Several techniques are known for conveying to printing system information about the contents of a paper tray. One technique uses a single paper tray that can be configured to receive various sizes of paper. Many home and small-business printers utilize such a single paper tray. However, re-configuration only accommodates a series of discrete paper sizes, such as letter-sized, legal-sized and A4-sized paper. Typically, a series of notches or holes is provided in the tray, and one or more media stops are positioned into a selected set of notches or holes to accommodate one of the available paper sizes. However, only a handful of predefined discrete paper sizes are available.
According to even another technique, a printing system uses a look-up table that monitors the position of microswitches that indicate the received print media size. In the past, this has been achieved by using a series of switches and the logic of on/off switch positions to detect the presence of common paper sizes. However, paper size can only be determined in accordance with the predetermined location of the switches and does not determine specific sheet sizes since the switches are incrementally arranged.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a print media size detector capable of detecting an infinite number of media sizes within a range of sizes. Furthermore, there is a need for an improved paper tray utilizing such a media size detector.